Some info I found...
http://www.expertvillage.com/video/2202_show-dog-stand-part1.htm
http://www.ehow.com/video_2041600_teach-dog-stand-command.html
http://www.pedigreedatabase.com/gsd/bulletins_read/62053.html#62062
http://www.pedigreedatabase.com/gsd/bulletins_read/193398.html
It sounds like you are teaching it properly, but it may just take some time to really get it. And teaching to stack is actually I think a couple of commands tied together. First your dog has to stand, then accept that it can be posed, and then hold the position/stay. Which may be kind of hard for a puppy that is easily distracted.
While I am certainly no expert, and am struggling myself to understand how to best teach this... I think this is why many people say you need 2 or 3 people to get a good stacked shot. You need to give the dog something to focus on. In the ring many people use food bait, and toss it in front of the dog, My dog likes his ball. When I want him to stand still, I tell him when he is standing to WAIT(not move) and then toss his ball a foot or two in front of him. If he is focused on the ball, he will then let me mess with his feet somewhat to place them. Now this is just good enough to have someone snap a few pictures before I have to release him to go grab his ball.
http://www.expertvillage.com/video/2202_show-dog-stand-part1.htm
http://www.ehow.com/video_2041600_teach-dog-stand-command.html
http://www.pedigreedatabase.com/gsd/bulletins_read/62053.html#62062
http://www.pedigreedatabase.com/gsd/bulletins_read/193398.html
It sounds like you are teaching it properly, but it may just take some time to really get it. And teaching to stack is actually I think a couple of commands tied together. First your dog has to stand, then accept that it can be posed, and then hold the position/stay. Which may be kind of hard for a puppy that is easily distracted.
While I am certainly no expert, and am struggling myself to understand how to best teach this... I think this is why many people say you need 2 or 3 people to get a good stacked shot. You need to give the dog something to focus on. In the ring many people use food bait, and toss it in front of the dog, My dog likes his ball. When I want him to stand still, I tell him when he is standing to WAIT(not move) and then toss his ball a foot or two in front of him. If he is focused on the ball, he will then let me mess with his feet somewhat to place them. Now this is just good enough to have someone snap a few pictures before I have to release him to go grab his ball.